Our experiment with a new ad provider does not seem to have worked out, those
notices about weird mobile redirects was followed by some other warnings about
dodgy sites, so their ad code has been replaced with code known to be reliable,
if not particularly productive. My apologies for the situation, which went on
longer than it should have, as it seemed like it was being worked out all along
the way. This should be sorted now, so please let me know immediately if it
isn't.